Bifurcation Analysis of a Marine Food Chain

Abstract

Bifurcation theory and dynamical systems techniques were used to analyze the joint effect of contaminants and nutrient loading on population dynamics of marine food chains. Contaminant toxicity is assumed to alter mortality of some species with a sigmoidal dose-response relationship. A generic effect of pollutants is to delay transitions to complex dynamical states towards higher nutrient load values, but more counterintuitive consequences arising from indirect effects are described. In particular, the top predator seems to be the species more affected by pollutants, even when contaminant is toxic only to lower trophic levels